Enhanced Oil Recovery (EOR) may be used to increase oil recovery in fields worldwide. There are three main types of EOR, thermal, chemical/polymer and gas injection, which may be used to increase oil recovery from a reservoir, beyond what can be achieved by conventional means—possibly extending the life of a field and boosting the oil recovery factor.
Thermal enhanced recovery works by adding heat to the reservoir. The most widely practiced form is a steam drive, which reduces oil viscosity so that it can flow to the producing wells. Chemical flooding increases recovery by reducing the capillary forces that trap residual oil. Polymer flooding improves the sweep efficiency of injected water. Miscible injection works in a similar way as chemical flooding. By injecting a fluid that is miscible with the oil, trapped residual oil can be recovered.
Referring to FIG. 1, there is illustrated prior art system 100. System 100 includes underground formation 102, underground formation 104, underground formation 106, and underground formation 108. Production facility 110 is provided at the surface. Well 112 traverses formations 102 and 104, and terminates in formation 106. The portion of formation 106 is shown at 114. Oil and gas are produced from formation 106 through well 112, to production facility 110. Gas and liquid are separated from each other, gas is stored in gas storage 116 and liquid is stored in liquid storage 118.
U.S. Pat. No. 2,859,818 discloses a method for recovering petroleum from a formation by injecting a solvent. The solvent may be a hydrocarbon solvent such as alcohols, gasoline, kerosene, dimethyl ether, other hydrocarbons having from 2 to 5 carbon atoms, or mixtures. U.S. Pat. No. 2,859,818 is herein incorporated by reference in its entirety.
U.S. Pat. No. 2,910,123 discloses a method for recovering petroleum from a formation by injecting a solvent. The solvent may be a hydrocarbon solvent such as alcohols, gasoline, kerosene, dimethyl ether, other hydrocarbons having from 2 to 5 carbon atoms, or mixtures.
PCT Patent Application Publication WO 2010/02693 discloses a method comprising recovering a carbon source from a formation; converting at least a portion of the carbon source to a synthesis gas; converting at least a portion of the synthesis gas to an ether; and injecting at least a portion of the ether into the formation.
PCT Patent Application Publication WO 2008/141051 discloses a system for producing oil and/or gas from an underground formation including a well above the formation; a mechanism to inject an enhanced oil recovery formulation into the formation, the enhanced oil recovery formulation including dimethyl ether; and a mechanism to produce oil and/or gas from the formation.
PCT Patent Application Publication WO2011/140180 discloses a system for producing oil and/or gas from an underground formation comprising a well above the formation; a mechanism to inject an enhanced oil recovery formulation into the formation, the enhanced oil recovery formulation comprising water and an additive; and a mechanism to produce oil and/or gas from the formation.
There is a need in the art for improved systems and methods for enhanced oil recovery. There is a further need in the art for improved systems and methods for enhanced oil recovery using a solvent enhanced water flood. There is a further need in the art for improved systems and methods for improving the recovery and recycling of a solvent from a EOR flooding operation.